What Does Sedimentation Mean?
Sedimentation is the process of depositing sediment. It is a treatment process in which the velocity of the water is lowered below the suspension velocity and the suspended particles settle out of the water due to gravity, centrifugal acceleration or electromagnetism. Sedimentation has been used to treat wastewater for millennia. Most water treatment plants include sedimentation in their treatment processes.
Sedimentation of corrosive particles in boilers increases scale buildup, which leads to corroded boiler walls and heat loss.
Sedimentation is also known as settling or clarification.
Corrosionpedia Explains Sedimentation
In water treatment, sedimentation is the process of removal of suspended particles that are heavier than water by gravitational settling. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans. Settling basins and clarifiers can be used for removal of solids deposited by sedimentation.
Sedimentation is widely employed in:
- Water purification
- Sewage treatment
- Storm-water treatment
- Industrial wastewater treatment
Sedimentation causes component clogging and malfunctions, which leads to increased corrosion rate. It also causes sediment deposits in water treatment plants and scale formation in boilers, which ultimately leads to process inefficiency, corrosion and boiler failure.
Sedimentation in potable water treatment generally follows a step of chemical coagulation and flocculation, which allows grouping particles together into flocs of a bigger size. This increases the settling speed of suspended solids and allows settling colloids.
In sewage treatment, sedimentation is removal of floating and settleable solids through sedimentation. The purpose of sedimentation here is to decrease the concentration of suspended particles in the water, reducing the load on the filters.
The sedimentation process can be used to treat raw water containing suspensions ranging from a very low concentration of tiny particles to a high concentration of flocculent solids.